Light-responsive melanopsin is found in many parts of the human brain. Melanopsin is a photopigment relevant to regulation of Circadian rhythms and other non-visual responses to light. It is most sensitive to blue light, but is also sensitive to other wavelengths of light in the visible spectrum.
WO 2008/029001 has disclosed that photo-sensitive intracranial nerve tissue can be stimulated via the ear canal. The in-ear light treatment makes use of bright light in the visible spectrum. The ear canal absorbs the light radiation, and radiation energy will be transmitted through the ear canal to regions of the intracranial nerve tissue containing melanopsin. Thus a biological effect can be created through visible-spectrum light which is provided in the ear canal. This has been substantiated through a number of recently published papers which include the following.
“A New Independent User Study Published: Bright Light Headset Benefits are Comparable to Those of Bright Light Lamps” (http://www.prnewswire.com/news-releases/a-new-independent-user-study-published-bright-light-headset-benefits-are-comparable-to-those-of-bright-light-lamps-179445141.html).
“Light-Responsive Melanopsin Found in Many Parts of the Human Brain” (http://www.prnewswire.com/news-releases/light-responsive-melanopsin-found-in-many-parts-of-the-human-brain-152310145.html).
“The Emerging Roles of Melanopsin in Behavioral Adaptation to Light (Megumi Hatori and Satchidananda Panda, The Salk Institute for Biological studies, http://panda.salk.edu/pdf/emergingrolesofmopn4.pdf).
The in-ear light treatment may also be integrated into a combined audio and light-emitting headset.
Further, EP 2,550,993 has disclosed that non-ocular light treatment can be provided not only through the ear canal, but also from other extracranial positions. These include positions below the “equatorial line” of the head formed by the cerebrum, from where light energy can reach regions located near the brain stem. This document also notes the presence of other photosensitive proteins which can be stimulated from such positions.
Non-ocular light treatment has been disclosed for treatment of various disorders including Seasonal Affective Disorder (SAD), migraines, anxiety, Obsessive Compulsive Disorder (OCD), and alcohol and nicotine addiction.
U.S. Pat. No. 6,350,275 B1 discloses a device for treating a circadian rhythm disorder in a subject. The device includes a plurality of light emitting diodes (LED's), preferably blue to green; a mounting to which the LED's are connected: a material for positioning the LED's within 3 cm of the subject, with an orientation toward the subject; a portable power supply electrically connected to the LED's; and a control connected to the LED's for altering the operation of the LED's.